1. Field of the Invention
Embodiments of the invention relate to an apparatus used during the vaporization of chemical precursors. More particularly, the invention relates to a splash guard used within an ampoule during a vapor deposition process.
2. Description of the Related Art
Chemical vapor deposition (CVD) and atomic layer deposition (ALD) are known techniques for forming a material on a substrate by the reaction of vapor phase chemicals near the surface of a substrate. In general, CVD and ALD techniques involve the delivery of gaseous reactants to the substrate surface where a chemical reaction takes place under temperature and pressure conditions favorable to the thermodynamics of the reaction. The type and composition of the layers that may be formed using a CVD process or an ALD process are limited by the ability to deliver a chemical reactant or precursor to the substrate surface. Various liquid precursors have been successfully used during CVD and ALD applications by delivering the liquid precursors within a carrier gas.
In the prior related art, a carrier gas is usually passed through a heated container containing a volatile liquid precursor at conditions conducive to vaporize of the precursor. The carrier gas combines with the vaporized precursor and both are drawn from the container to the reaction chamber. Prior known liquid precursor delivery apparatuses and procedures have been unsuccessful in reliably delivering the precursor to the reaction chamber. In some cases, the liquid precursor is vaporized within the container but condenses throughout the conduit or tubing of the delivery line. The temperature of the container or the flow rate of the carrier gas may be increased to prevent condensation within the delivery line in some processes, if the chemical precursor or the fabrication process can tolerate such temperature or flow rate.
Bumping or splashing of the chemical precursor is another problem encountered while using a liquid precursor during a vapor deposition process. Splashing occurs when a portion of the chemical precursor is ejected away from the main supply of precursor by the introduction of a carrier gas into the ampoule. Often, the precursor, in a liquefied state, is bumped or splashed into the outlet of the ampoule and may block the delivery line, clog valves or contaminate the substrate surface.
Therefore, there is a need for an apparatus and process to deliver vaporized chemical precursors from a container while preventing or limiting non-vaporized chemical precursors out of the container during a fabrication process.